In the state of the art for transmissions with at least two countershafts, the free gears which serve as main shaft gears are placed radially in both the gears of the countershafts. The main shaft gears are placed on the main shaft in the axial direction with the help of washer discs whereby a washer disc of the free gear is arranged between the washer discs arranged on the main shaft. There is a disadvantage here whereby due to production tolerances and due to the gaps required for oiling, a large play arises so that when the mass of the free gears vibrate as a result of the wobbling of the main shaft or as a result of rotational movements and thus cause an unpleasant rattling noise.
With reference to EP 0 361 685 A1, for a transmission with one countershaft it was suggested that the gear of the drive arranged on the countershaft be placed on the countershaft in such a way that the vibration of the gear is not transferred to the countershaft by a small play and through an attenuating element joined to the gear and parallel to the countershaft. The rattling noise could also be reduced as a result of this. This construction proved to be expensive and the rattling noise could not be completely suppressed since the other gears arranged on the countershaft are in contact with the corresponding free gears of the drive shaft without any further constructive measures.
In addition, it is also known that in the case of axial placement of the main shaft gears another additional disc is placed near the washer disc of the main shaft which is between the two washer discs of the main shaft. This disc is fixed firmly to the main shaft gear and is supported by the front end of the gear teeth of the countershaft or the intermediate shaft used for the reverse gear. The main shaft gear is also pressed or pushed against the disc through spring action. In the case of such a construction, the assembly could prove to be disadvantageous.
The following invention has the objective of designing a device for reduction of the axial movement of the main shaft gears in a transmission with at least two countershafts which overcomes this disadvantage of the state of the art. The innovative construction should be especially cost effective to produce and easy to assemble.